Redmine改善活動では、実装済のコードを読んで学べることもあります

% grep -rn "IssueCustomField" * --exclude-dir={vendor,public,tmp,doc,log,test,config/locales,files,coverage,spec,node_modules}
app/models/project.rb:58:                          :class_name => 'IssueCustomField',
app/models/project.rb:640:      @all_issue_custom_fields ||= IssueCustomField.
app/models/project.rb:644:      @all_issue_custom_fields ||= IssueCustomField.
app/models/project.rb:658:      @rolled_up_custom_fields ||= IssueCustomField.
app/models/issue_custom_field.rb:20:class IssueCustomField < CustomField
app/models/custom_field.rb:115:    if %w(IssueCustomField TimeEntryCustomField ProjectCustomField VersionCustomField).include?(self.class.name)
app/models/custom_field.rb:118:    if self.is_a?(IssueCustomField)
app/models/issue.rb:692:      IssueCustomField.where(:visible => false).
app/models/query.rb:631:      IssueCustomField.sorted
app/controllers/custom_fields_controller.rb:34:          IssueCustomField.where(is_for_all: false).joins(:projects).group(:custom_field_id).count
app/controllers/projects_controller.rb:97:    @issue_custom_fields = IssueCustomField.sorted.to_a
app/controllers/projects_controller.rb:104:    @issue_custom_fields = IssueCustomField.sorted.to_a
app/controllers/projects_controller.rb:141:    @issue_custom_fields = IssueCustomField.sorted.to_a
app/controllers/projects_controller.rb:200:    @issue_custom_fields = IssueCustomField.sorted.to_a
app/views/custom_fields/_index.html.erb:6:    <% if tab[:name] == 'IssueCustomField' %>
app/views/custom_fields/_index.html.erb:19:      <% if tab[:name] == 'IssueCustomField' %>
app/views/custom_fields/_index.html.erb:21:      <td><%= l(:label_x_projects, :count => @custom_fields_projects_count[custom_field.id] || 0) if custom_field.is_a? IssueCustomField and !custom_field.is_for_all? %></td>
app/views/custom_fields/formats/_text.html.erb:3:<% if @custom_field.class.name == "IssueCustomField" %>
app/views/custom_fields/_form.html.erb:45:    <% if %w(IssueCustomField UserCustomField ProjectCustomField VersionCustomField GroupCustomField TimeEntryCustomField).include?(@custom_field.class.name) &&
app/views/custom_fields/_form.html.erb:50:    <% if %w(IssueCustomField ProjectCustomField).include?(@custom_field.class.name) && @custom_field.format.searchable_supported %>
app/views/custom_fields/_form.html.erb:56:  <% if %w(IssueCustomField TimeEntryCustomField ProjectCustomField VersionCustomField).include?(@custom_field.class.name) %>
app/views/custom_fields/_form.html.erb:60:  <% if @custom_field.is_a?(IssueCustomField) %>
app/views/custom_fields/index.api.rsb:30:      if field.is_a?(IssueCustomField)
app/views/trackers/_form.html.erb:26:<% @issue_custom_fields = IssueCustomField.sorted %>
app/helpers/custom_fields_helper.rb:23:    {:name => 'IssueCustomField', :partial => 'custom_fields/index',
app/helpers/custom_fields_helper.rb:218:      default_type = 'IssueCustomField'
lib/redmine/helpers/time_report.rb:139:        custom_fields += @project.nil? ? IssueCustomField.visible.for_all : @project.all_issue_custom_fields.visible